Summary Neglected tropical diseases (NTDs) are a diverse group of diseases with distinct characteristics that thrive mainly among the poorest populations of the world. There are 17 NTDs prioritized by the World Health Organization which are endemic in 149 countries and affect more than 1.4 billion people globally, which costs these developing economies billions of dollars annually. The neglected tropical diseases result from four different causative pathogens: protozoa, bacteria, helminth and virus. The majority of the diseases lack effective treatments. For example, 6 to 7 million people in Latin America are infected with the eukaryotic parasite Trypanosoma cruzi, the causative agent of Chagas disease. This disease is gaining recognition as an emerging infection in the United States where an estimated 300,000 people may be infected. Chagas disease has a serious economic impact on the United States and the world. The cost of treatment in the United States alone, where the disease is not indigenous, is estimated to be $900 million annually, which includes hospitalization and medical devices such as pacemakers. The global cost is estimated at $7 billion. Unfortunately, there are no FDA approved treatments for Chagas disease and the two available treatments used outside the U.S. have toxic side effects. New therapeutics for Chagas disease and the other NTDs are desperately needed. Using a machine learning model based on published data for compounds tested against T. cruzi we have identified the EU-approved antimalarial pyronaridine as particularly active in vitro and in vivo with statistically significant efficacy in a 4-day mouse model of infection with a T. cruzi strain expressing firefly luciferase. Pyronaridine demonstrated 85.2% parasite reduction after 4 days treatment, and is known to have a long half-life in humans (13.2 days), promising toxicity profile (less toxic than chloroquine in malaria treatment) and may suggest a drug repurposing opportunity for further study. We propose in this project to determine the minimum effective dose (treatment regimen) for pyronaridine in the acute model of Chagas disease. We will also determine efficacy in the chronic phase of Chagas disease (sterile cure). We will pursue combination therapy DMPK profiling as well as performing combination therapy in vivo efficacy in chronic model of Chagas disease. The results will enable us to assess whether this EU approved drug is worthy of a clinical trial for Chagas disease in the UH3 stage. If successful we will design a clinical study and recruit patients for a phase II trial. This grant represents a unique opportunity to partner the Center for Discovery and Innovation in Parasitic Diseases (www.cdipd.org) at UCSD and the University of Sao Paulo in Brazil with Collaborations Pharmaceuticals Inc.